Answer: The placebo effect
Explanation: The placebo is an inert substance or treatment that doesn't have any therapeutic value. Examples of placebos are sterile water, saline solution and sugar pill. Sham surgery, and other procedures too.
A placebo is anything that seems to be a "real" medical treatment but in actual sense it isn't. It could be a pill, a shot, or some other types of medication.
The idea that is that your brain can convince your body that a fake treatment is the real thing and this is called the placebo effect.
Hence the placebo effect is defined as a phenomenon in which some people experience a benefit after the administration of an inactive substance or sham treatment.